feat(ift): EventHub AI Router stack for Zed

FastAPI gateway with A/B/C lane orchestration, LiteLLM proxy config,
Swarm stack (postgres, redis, VPN off-by-default), deploy/smoke/audit scripts.

router/rules_loader.py

@@ -0,0 +1,39 @@
+"""Load routing YAML configs from CONFIG_DIR."""
+
+from __future__ import annotations
+
+import os
+from functools import lru_cache
+from pathlib import Path
+from typing import Any
+
+import yaml
+
+CONFIG_DIR = Path(os.environ.get("CONFIG_DIR", "/app/config"))
+
+
+@lru_cache(maxsize=1)
+def load_routing_rules() -> dict[str, Any]:
+    path = CONFIG_DIR / "routing_rules.yaml"
+    with path.open(encoding="utf-8") as f:
+        return yaml.safe_load(f) or {}
+
+
+@lru_cache(maxsize=1)
+def load_model_matrix() -> dict[str, Any]:
+    path = CONFIG_DIR / "model_matrix.yaml"
+    with path.open(encoding="utf-8") as f:
+        return yaml.safe_load(f) or {}
+
+
+@lru_cache(maxsize=1)
+def load_orchestration() -> dict[str, Any]:
+    path = CONFIG_DIR / "orchestration.yaml"
+    with path.open(encoding="utf-8") as f:
+        return yaml.safe_load(f) or {}
+
+
+def reload_configs() -> None:
+    load_routing_rules.cache_clear()
+    load_model_matrix.cache_clear()
+    load_orchestration.cache_clear()